An organic optoelectronic device is, for example, an organic light emitting diode (“OLED”) display, an OLED light source used for general purpose lighting, an organic light sensor array, an organic solar cell array, or an organic laser. The OLED display can be, for example, a passive matrix display, an alpha-numeric OLED display, or an active matrix OLED display. In the specific case of the OLED display, the display is typically comprised of an anode layer and a cathode layer where the anode layer is typically patterned to form multiple anode strips and cathode layer is patterned to form multiple cathode strips. The anode strips intersect the cathode strips, and pixels are formed at the intersections of the anode strips and the cathode strips by sandwiching one or more organic layers between the anode strips and the cathode strips. The one or more organic or semi-organic layers sandwiched between the anode and cathode include a light emitting layer which emits light upon charge recombination.
The organic optoelectronic device requires protection from reactive agents such as water vapor in the atmosphere, and therefore employ some form of encapsulation. One common procedure to encapsulate the organic electronic device is to sandwich it between a substrate and an encapsulation lid, and a continuous adhesive layer around the perimeter of the device bonds together the substrate and the encapsulation lid such that the device is sealed. The adhesive layer is typically not impermeable to oxygen and particularly not to moisture, so the encapsulated device package will generally have some finite permeation rate. These reactive gases that permeate through the adhesive layer react with the cathode layer and prevent electron injection at the sites of reaction. The reactive gasses that permeate through the adhesive seal react with the cathode layer at, for example, pinholes in the cathode layer or at the edges of the cathode strips. Eventually, the sites of reaction reach some specified quantity, and the device is considered no longer useable.
Employing getter materials inside the package can extend the useable lifetime of the device. These getter materials absorb and/or react with the water vapor that would otherwise harmfully react with other OLED materials. Typical getter materials include zeolite, zeolitic clays, CaO particles, BaO particles, Ba metals and so on.
Zeolite getters are thin tablets made of compressed clay that are thermally activated just prior to being placed in the OLED packaging (prior to being encapsulated). Thermal activation is performed in an oven at temperatures from nominally 250 to 400 degrees C. Once thermally activated, the tablets should remain in a moisture-free (<10 ppm water vapor) environment until sealed in the OLED package. Because the tablets have minimal binding agents to maintain their structural integrity, the tablets are highly prone to particle sloughing. The fragile nature of the compressed clay tablets makes them extremely difficult to handle and place into the OLED package. Particle sloughing and tablet breakage cause an unacceptable amount of particles to be generated in the process, resulting in significant yield losses.